A little over a year ago, Jim Tittle was stunned to learn that a piece of land down the road from a family property near Red Wing had recently sold for $1.5 million.

“I know what my land is supposed to be worth,” Tittle said. “I looked at that and thought: Oh my god, what’s going on here?”

Even record-high farmland values didn’t explain why someone would pay that much for the parcel as well as another $1.1 million for a plot across Highway 58. “Somebody was valuing that land for something besides farming,” Tittle concluded.

With a little sleuthing Tittle, a St. Paul filmmaker, learned the land was bought by a company that hopes to mine it for fine silica sand, a commodity whose value has surged because of demand from oil and gas drilling operations.

The particular type of sand, which is common in the bluffs along the Minnesota-Wisconsin border, has come to be known as “frac sand” because of its use in hydraulic fracturing, a drilling practice in which water, chemicals and sand are blasted underground to loosen oil and gas deposits.

Wisconsin has already seen an explosion of new mining activity, and Minnesota is in line for a piece of the sand rush, too — if local governments decide to allow it. Many cities and counties have passed moratoriums on new sand mines while they evaluate the potential risks and benefits.

Since 2004, demand for frac sand has been growing at a 28 percent annual clip, according to U.S. Silica Holdings, the nation’s second-largest silica producer. Prices have risen about 9 percent annually to more than $30 per ton.

Sand mining has potential to bring jobs and tax revenue to Minnesota communities, as well as a handful of big paychecks for property owners, like Tittle’s neighbors, who are sitting on the right piece of geology.

It also means increased truck traffic, spoiled views and possible health impacts. The sand is much finer than the stuff in playground sandboxes, which means it can be easily inhaled. Workers who breathe the dust may be at risk for lung cancer and silicosis, in which scar tissue forms in the lungs, reducing their ability to absorb oxygen. Little is known, however, about the risks of broader exposure to silica dust.

The Minnesota Pollution Control Agency is trying to determine whether the existing rules for sand and gravel mining are sufficient for frac sand.

Filmore, Goodhue, Houston, Wabasha and Winona counties have all passed moratoriums on new facilities. There are six existing silica sand mines in the state, all of which predate the recent frac sand boom, which so far has been muted in Minnesota because of the restrictions.

It hasn’t been invisible, though.

Winona saw a “noticeable” increase in dust and truck traffic last year, said Assistant City Planner Carlos Espinosa. Frac sand is mined in Wisconsin and hauled across the border for processing and shipping. The city estimates the activity has created more than 50 jobs with average annual wages exceeding $50,000, Espinosa said. Still, the city adopted a moratorium on new sand operations until March.

Winona County Assessor Stephen Hacken said he hasn’t seen any land sales that appear to be related to frac sand. Goodhue County Assessor Peggy Trebil said she’s aware of only three related parcels, which include the piece of land south of Tittle’s family property.

Tittle’s curiosity led him to begin filming a documentary called “The Price of Sand.” He has interviewed Wisconsin residents about how frac sand mining is affecting them. One of the more concerning themes is the rift it creates when one family gets rich at the expense of their neighbor’s peaceful view.

John Kronebusch, a Winona Realtor with Property Brokers of Minnesota, said he knows a few people who are trying to sell their homes now rather than risk having to sell later when a frac sand mine is next door.

Overall, though, he suspects the actual impact on land values will be confined to a handful of properties, with a few winners, a few losers, and a lot of jealousy.

“A lot of people don’t like the guy who wins the lottery,” Kronebusch said. But for the farmer who has the right piece of land? “It’s gonna be a heck of a lot better than corn and beans and raising cows, if this goes through.”